1. Field
Embodiments described herein relate generally to a differential signal output device and a portable device.
2. Background Art
In recent years, differential transmission standards such as low voltage differential signaling (LVDS) and high-definition multimedia interface (HDMI) have been widely used as means for transmitting a large number of signals between digital devices such as televisions, PCs, and mobile phones through a small number of wires.
In order to transmit a data signal with a driver at a rate exceeding 1 Gbps, the rise time and fall time of the data signal have to be a high slew rate of, for example, several hundreds ps.
However, a signal outputted from the driver with a high slew rate may cause emission of high-frequency noise of, for example, electromagnetic interference (EMI).
Thus the slew rate of the output signal from the driver has to be properly controlled according to transmission standards for transmitting data between digital devices, transmission lines that connect devices, and so on.